Semiconductor wafer processing typically can be carried out at non-standard temperature and pressure, such as vacuum, sub atmospheric pressure, or over pressure environments. Solutions used in processing wafers such as etchants and reactants, are composed of varied chemistries, both simple and complex. Often, obtaining an exact chemistry composition is critical to the success of a process step. Unfortunately, the nature of the processing environment is that the process steps are performed within sealed environments, to control the processing environment and obtain the desired chemistry. Such a sealed environment is not conducive for monitoring and analyzing conditions within the sealed environment, in particular the solution contained within the sealed environment. There exists a need to better monitor and analyze a solution within a sealed environment. Monitoring and analyzing high pressured sealed environments are particularly difficult, and dangerous, due to the nature of the high pressure. There is therefore also a need to better monitor and analyze a solution within a high pressure sealed environment.
In semiconductor manufacturing, defects and other problems are observed on output wafers. Such wafer defects are often attributable to improper solution process chemistries and environments used in the wafer process steps. Although process engineers are aware of external elements added to the processing environment, it is often unknown what residual chemistries exist in the processing environment prior to the introduction of the external elements. Attempts to completely clean a processing environment seldom if ever result in a 100% clean environment. Therefore, despite efforts to clean the processing environment, an unknown amount of residual elements remain prior to each new processing step. There exists a need to monitor the conditions within a closed environment to account for both residual and externally added elements.
A conventional monitoring practice for closed loop environments includes collecting exhaust generated from the processing environment. Unfortunately, collecting exhaust does not provide real time measurements of the processing environment. There is a need to monitor and analysis a closed loop processing environment in real time.